Here is a fact causing Republicans to wonder why Mitt Romney isn’t the runaway favorite in his campaign to unseat President Obama: No U.S. president since Franklin Roosevelt has won reelection when the unemployment rate was more than 7.4 percent.

So why isn’t Romney the clear favorite? Because Obama remains more popular personally than one would otherwise expect. Because the Obama campaign has been more effective at sowing doubt about Romney’s record as a wealthy capitalist than the Romney campaign anticipated, which is evidence to some that Romney’s campaign isn’t overstaffed with brilliant strategists. And because Romney himself has the unfortunate tendency to come off as both artificial and superficial.

Even Romney’s allies know he lacks the chemical building blocks of likability. The Republican speaker of the House, John Boehner, was asked recently by a voter in West Virginia the following lamenting question: “Can you make me love Mitt Romney?” Boehner answered, in a plain-spoken manner, “The American people probably aren’t going to fall in love with Mitt Romney.”

Many of Romney’s problems arise from his lack of authenticity. This suggests that he should choose a running mate who conveys a feeling of he-just-can’t-help-himself genuineness. Which is why all the talk about Romney’s unwillingness to consider New Jersey Gov. Chris Christie for the vice- presidential slot is a bit of a mystery to me.

There are, to be fair, many reasons Romney might want to keep Christie off the ticket. Christie has an excessively large mouth. He is easily provoked. He turns up late to speeches on occasion. He doesn’t quit when he’s ahead. He is no one’s idea of a deputy. He comes from a state the Republicans can’t win, no matter what Romney does. He is a Northeastern laissez-faire Republican mistrusted by social conservatives. And, of course, he is unwieldy and overweight and makes Romney look anorexic by comparison.

On the other hand, if Romney wanted to actually win the presidency, he might consider choosing Christie.

I’ve been looking at Romney’s vice-presidential possibilities for the past couple of weeks (yes, I know, I need to find a better hobby), and I’ve been struck by two things. The first, as The Washington Post columnist Michael Gerson has noted, is that the field of Republican vice-presidential hopefuls is much more impressive than was the field of Republican presidential hopefuls. (My apologies to fans of Michele Bachmann and Herman Cain.)

The second is that the most talked-about candidates, while in possession of impressive resumes, are almost comically bland. The first rule when picking a vice-presidential running mate is, of course, don’t pick Sarah Palin, or anyone who might remind the voting public of Sarah Palin. The people on Romney’s short list — which includes Ohio Sen. Rob Portman, former Minnesota Gov. Tim Pawlenty and Wisconsin Rep. Paul Ryan — do not resemble Palin in any way. Romney is safe with any of these candidates.

Will he fill arenas with them? Are any of these candidates particularly skilled at speaking to disaffected blue-collar workers, to Reagan Democrats, without condescension? Pawlenty has a blue-collar background, but he didn’t connect with the white working class, or with anyone else, in his abbreviated run for president.

Let me put it another way. Do any of these candidates match Christie’s preternatural ability to explain Republican deficit-reduction ideas without coming off as bloodless budget-cutters?

I’ve spent some time following Christie across New Jersey, to town-hall meetings mainly, but also on visits to social-service agencies and, most entertainingly, to a Bruce Springsteen concert in Newark. His town halls are famous for their confrontational tone, but in truth, shouting matches are rare. What isn’t rare are huge, overflow crowds. I attended events, mainly in high-school gymnasiums, over the past few months, and at each one fire marshals had to cap attendance.

Why do people come by the hundreds to weekday morning meetings in small towns? Because Christie gives them something they want. Not so much the sarcasm (which can be enjoyable), but the skillful, tenacious and blunt articulation of just where New Jersey’s government has gone off the rails — in its budget-making, in its management of state-worker pensions and in its uncanny ability to create unfunded mandates. No one in national politics does a better job of arguing against deficit spending than Christie.

An easy prediction: Christie would be filling basketball arenas with wildly enthusiastic fiscal conservatives within two weeks of being chosen as Romney’s running mate.

Another easy prediction: It ain’t going to happen.

The downside risk of a Christie pick is fairly small. But from what I understand, Romney is looking for someone who presents no downside at all. This comprehensive aversion to risk might be at the core of the problems plaguing his campaign. If the campaign does figure out that it needs to balance Romney’s upper-crust manner with someone who has actual middle-class, even working-class, credentials, it might very well go with Pawlenty. Pawlenty lost his nerve in the Republican primaries, but he was a talented governor.

Can he energize arenas crammed with Republicans looking for inspiration? Doubtful. But nothing the Romney campaign has done so far suggests that it is interested in energizing voters.

Jeffrey Goldberg is a Bloomberg View columnist and a national correspondent for The Atlantic.